secondary refining

Secondary refining refers to the process of obtaining lead from scrap materials, primarily discarded automobile batteries. This process accounts for a significant portion of refined lead output because secondary lead is easily melted and refined, and it rarely becomes contaminated during use.1

The recycling of lead from battery scrap involves several steps:
* Scrap Treatment and Separation: The batteries are processed to separate the lead components.1
* Smelting: The lead-containing fractions are then smelted, typically in reverberatory and blast furnaces, to extract the lead bullion.1
* Refining and Alloying: The lead bullion is refined and alloyed into commercial products. Secondary lead recovered from batteries often contains antimony and other metals, which are frequently resold to battery manufacturers. Lead containing tin is repurposed for solder and bearing metals.1

Calcium-lead alloys can also be produced from recycled lead by removing antimony through oxygen injection and then casting the molten lead into blocks. Some primary refineries also process secondary lead, increasingly using rotary furnaces for this purpose.1